prop sag--new mounts or shim existing mounts?

[jetdriven]

cut slots in the lower mount shims, loosen the lower bolts with the engine pulled up by a hoist and drive them in.  you can do this in 2 hours easily.

[OR75]

cut slots in the lower mount shims, loosen the lower bolts with the engine pulled up by a hoist and drive them in.  you can do this in 2 hours easily.

 

 

can you describe how you changed the mounts (not the shims) ? did you hire a contortionist ? 

 

 

Are you thinking about STC'ing your cowl fix ?

[jetdriven]

can you describe how you changed the mounts (not the shims) ? did you hire a contortionist ? 

 

 

Are you thinking about STC'ing your cowl fix ?

I changed the mounts 2 year ago with the new engine.  Shims are easy to do.

 

The cowl fix is a minor alteration, just like the LASAR cowl fix kit.

Major alteration means an alteration not listed in the aircraft, aircraft engine, or propeller specifications -

(1) That might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or 2) That is not done according to accepted practices or cannot be done by elementary operations.

[OR75]

mounts change is straightforward at engine change.

[M20S Driver]

My boss was talking about the engine mounts on the 2002 Ovation he takes care of.  The ones in the catalog crush down after a couple years, while Lord makes a more durable mount that fits in the same place, its not approved for the Ovation.  Or as he understands it to be.

My parts catalog indicates that the engine mounts are manufactured by "Lord MFG". Are you referring to a different engine mount made by them?

Masoud

[M20S Driver]

Duplication!

[jetdriven]

My parts catalog indicates that the engine mounts are manufactured by "Lord MFG". Are you referring to a different engine mount made by them?

Masoud

Yes, a for different application. He called Lord and they said yes they made a stiffer mount but there was no way to put it on an Ovation.

[flyingvee201]

doubt you can do something without a hoist.

 

picture of the shim between the AN bolt and the rubber mount.

 

Those are Mooney parts and exist in different thickness

 

the top are easy to get to.

bottom ones are a pain in the bottom !!

Thanks!

But Im trying to figure out how the shim on the outside of the rubber mount makes any difference in the sagging.

The picture in my mind just see how this works. I see just the AN bolt being extended.

I would think the shim would have to be somewhere on the inside between the motor mount frame and the engine mount brace.

 

Sorry...Im not getting the picture in my head!!  LOL

[flyingvee201]

found this

http://www.donmaxwell.com/publications/MAPA_TEXT/Alining%20Engine%20Using%20Shims/ALIGNING_YOUR_ENGINE.HTM

[OR75]

Thanks!

But Im trying to figure out how the shim on the outside of the rubber mount makes any difference in the sagging.

The picture in my mind just see how this works. I see just the AN bolt being extended.

I would think the shim would have to be somewhere on the inside between the motor mount frame and the engine mount brace.

 

Sorry...Im not getting the picture in my head!!  LOL

you will easily get it once you have to cowling off

those big washers come in different thickness

[M20S Driver]

Does anyone know if the engine mount on io550 installed on Ovation or Eagle could be shimmed? I could not find anything on-line for the shimming of the mounts on the newer Mooneys.

Thanks,

Masoud

My conclusion is to leave it alone. After talking to a few MSCs and other experts, there is no shimming procedure since the io550 sits in a cradle. New mounts may improve it or fix it but will sag after a year or two.

Masoud

[slowflyin]

I'm replacing the mounts on my 70 F model but I'm second guessing the part number.  Lord shows the 70 F model but the serial number range is out of whack.  670001 through 22-1438.  Mine is #7000700.   Another chart just shows F models through 77.   Any suggestions?

 

joe

[Gary0747]

I have read all the engine mount shimming advice here and on Don Maxwell’s site. They all say to center the prop spinner in the cowling, but my question is shouldn’t the engine be canted to the  right slightly due to the P-Factor of the rotating prop?

[RLCarter]

1 hour ago, Gary0747 said:

I have read all the engine mount shimming advice here and on Don Maxwell’s site. They all say to center the prop spinner in the cowling, but my question is shouldn’t the engine be canted to the  right slightly due to the P-Factor of the rotating prop?

My guess is seeing how the engine mount has the centerline offset built into it and the cowl {nose} does too

[Guest]

10 hours ago, Gary0747 said:

I have read all the engine mount shimming advice here and on Don Maxwell’s site. They all say to center the prop spinner in the cowling, but my question is shouldn’t the engine be canted to the  right slightly due to the P-Factor of the rotating prop?

Engine offset to the right is more pronounced in many Piper products and their required shims are well laid out in the manual.  Mooney is more trial and error to get the engine to fit in the cowl opening.

Clarence

[PT20J]

The P-factor is only noticeable in climb and compensated with right rudder. In cruise, the main component causing a left yawing tendency is the spiraling slipstream hitting the vertical tail components. There are three ways to counteract this that I'm aware of: angling the engine thrust line, angling the vertical tail, offsetting the rudder center position. One, or a combination of all three can be used. I'm not sure what Mooney does, but any angling of the tail or engine must be pretty small since they aren't noticeable. The service manual does call for a 1 deg right rudder offset when rigging the rudder.

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